After spending the second half of 2010 training with Scottish club Celtic, US U-20 forward Adrian Ruelas has returned to Santos Laguna a vastly improved player who is dominating the youth levels in Mexico.

Ruelas, 19, had been with Santos Laguna for most of his youth career but in October, he went to Scotland to train with Celtic for the remainder of the year. While he was there, he played well in training with the club's first team and even managed to see the field in several friendlies for Celtic.

In January he then returned to Mexico which confounded some because it was unclear as to why he was not taken under loan by Celtic and to boot, the Glasgow club never offered a reason.

Ruelas was with Celtic as part of an exchange agreement between the two clubs and Ruelas did not have a European passport that would make a work permit difficult.

Ruelas admits that he would have liked to have stayed longer in Scotland but he is happy to be back at Santos.

He has emerged as a top forward to start the U-20 season in Mexico where he has scored an astonishing six goals through the first four games. Ruelas attributes a lot of this success to what he learned at Parkhead.

"The experience I had at Celtic was really positive," Ruelas told YA from Mexico. "I learned a lot of stuff. Instead of taking it as a negative way, I am taking it in a positive way. I am just going to keep going forward toward my goal which is to debut [for the first team] as soon as possible."

"I feel really good, I feel comfortable and more experienced. I've taken back with me the way [Celtic] thinks and the way they train. I think that all these little things kind of changed me in a way and it's going well so far this season."

It was always a dream for Ruelas to play in Europe and he did not expect it to happen quickly in his career. He does want to return to Europe again on full-time basis in the future and his time at Celtic now has given him an idea of what to expect when he does make the move.

"What I experienced in Scotland, when I go back to Europe I will now know what it's like and what to expect," Ruelas pointed out. "I think that with training with players that are World Cup quality that their abilities are contagious. Their way of thinking, playing, and how they pressure you into doing the right things. I think I got smarter in making my choices and runs. I now make better decisions."

For now, Ruelas is concerned with improving at Mexico and hopefully continue to impress at Santos. His strong start with the club's U-20 team has earned positive feedback from the coaches there and he is confident that he is much closer to the first team than he was before he left.

"As soon as I returned, I returned to the first team and I train with them every day and I play with the U-20s," Ruelas discussed. "The first thing the coaches told me when I came back was to take the Celtic experience as a positive and keep working because things will open up. I can see myself as closer. If there is an injury or a red card, I am ready to step in. I am at that point now. Things are going really great with the season."

Ruelas is now at the point where he is training with the first team at Santos while playing for the U-20 team. Before he left for Scotland in October, he was further down the club's pecking order however now, he feels strongly like he is a big part of the club. Things are clearly different now for Ruelas in a positive way.

"Training with the first team at Celtic on an everyday basis and now bringing it back here it's a little different," Ruelas said of how he now fits in at Santos. "Now this is where I think I was supposed to be maybe a year ago and training with the first team here. Now I can play and challenge them. I can also ask for advice. I can go up to [the first team players] and talk to them as if I am a level teammate."

Also on Ruelas' mind is the making the US U-20 national team for the upcoming World Cup qualifiers and possibly the World Cup team this summer. Ruelas has been part of US U-20 head coach Thomas Rongen's plans during 2010 and was the team's leading scorer during their Milk Cup championship with three goals.

But this U-20 team is one of the strongest and deepest youth teams ever for the US program and making the team is a challenge. Ruelas knows that playing for this team could continue to open doors for him professionally.

"I am looking forward to hopefully making the team and participating with the U-20s at the World Cup," The Fontana, California native said. "I want to do a great job if I get to play and get to go. From there it could open up opportunities."

The last time Ruelas played for the US U-20 team was in December when he took part in a camp. Ruelas was still in Scotland at the time and had picked up a back injury just prior to arriving in Florida to play with the US. Even though he was not at his best, he still wanted to play for his country.

"It was a big group with a lot of players," Ruelas recalled of the camp. "I felt okay but I wasn't great. The week before I picked up a little back injury and I was kind of struggling with it. But I wanted to go to that camp and I wanted to be there. I did not feel bad but I did not feel 100 percent. It was a short camp."

Now with US U-20 World Cup qualifying less than two months away, Ruelas is well aware of the talented American players in this U-20 cycle and the challenges that are ahead for making the team. Still he is confident that if he continues to play the way he has since returning to Mexico, he will get Rongen's attention once again.

"Obviously you want to catch the coach's eye," Ruelas concluded. "Sometimes I think I just have to go out and be myself. I have to play the way I play and not try to do things I can't. I will just keep doing what I have been doing that has been giving me results. There are a lot of good forwards on the [American] squad that have different qualities from one another. But I think I can do a good job with the team with my style of play."